Porphyry

Basanite

Porphyry and Basanite

Porphyry

Basanite

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Definition

Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix

Basanite is a black basaltic rock which mainly contains plagioclase, augite, olivine and nepheline and is formerly used as a touchstone

History

Origin

Egypt

Discoverer

Unknown

Etymology

From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites

From Latin basanites + -ite

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Plutonic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Porphyritic

Aphanitic to Porphyritic

Color

Black, Brown, Green, Grey, Red, Rust, White

Black, Brown, Green, Grey, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Glassy or Pearly

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Homes

Exterior Uses

Garden Decoration, Paving Stone

As Building Stone, Garden Decoration, Office Buildings

Other Architectural Uses

Curbing

Whetstones

Industry

Construction Industry

Construction Aggregate

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Monuments

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry

As a touchstone, Creating Artwork, Gemstone, In fire-starting tools, Manufacture of tools, Metallurgical Flux, Jewelry, To ignite fire, Used in flintlock firearms

Types

Rhomb Porphyry

Nepheline-Basanite, Analcite-Basanite and Leucite-Basanite

Features

Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny

Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate, Used as a touchstone

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Porphyry is formed in two stages: the magma cools slowly deep within the crust or the magma is cools rapidly as it erupts from a volcano, creating small grains that are usually invisible to naked eye.

Basanite is a fine-grained, hard rock that forms when bits of lava shoot out of volcanoes.

Composition

Mineral Content

Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica

Augite, Feldspar, Ilmenite, Olivine, Plagioclase

Compound Content

Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide

Potassium Oxide, Sodium Oxide, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering

Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

6-77

1 7

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Grain Size

Fine Grained

Fracture

Irregular

Uneven, Splintery or Conchoidal

Streak

White

Porosity

Less Porous

Highly Porous

Luster

Dull

Waxy and Dull

Compressive Strength

150.00 N/mm²100.00 N/mm²

0.15 450

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Cleavage

Toughness

1.7

1.5

Specific Gravity

2.5-42.5-2.8

0 8.4

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Transparency

Translucent to Opaque

Density

2.5-2.52 g/cm³2.7 g/cm³

0 1400

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Thermal Properties

Specific Heat Capacity

0.71 kJ/Kg K0.74 kJ/Kg K

0.14 3.2

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Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam

Africa

Egypt, Ethiopia, Ghana, South Africa

Uganda

Europe

Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland

Germany, Hungary, Italy, Spain

Others

Greenland

Greenland, Mid-Atlantic Ridge

Deposits in Western Continents

North America

Canada, Cuba, Jamaica, USA

USA

South America

Bolivia, Brazil, Colombia, Ecuador, Paraguay

Bolivia, Brazil

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Western Australia

New South Wales, New Zealand, Queensland, South Australia, Western Australia

All about Porphyry and Basanite Properties

Know all about Porphyry and Basanite properties here. All properties of rocks are important as they define the type of rock and its application. Porphyry and Basanite belong to Igneous Rocks.Texture of Porphyry is Porphyritic whereas that of Basanite is Aphanitic to Porphyritic. Porphyry appears Dull and Basanite appears Glassy or Pearly. The luster of Porphyry is dull while that of Basanite is waxy and dull. Porphyry and Basanite are available in black, brown, green, grey, red, rust, white colors. The commercial uses of Porphyry are creating artwork, gemstone, jewelry and that of Basanite are as a touchstone, creating artwork, gemstone, in fire-starting tools, manufacture of tools, metallurgical flux, jewelry, to ignite fire, used in flintlock firearms.